Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry
Research output: Contribution to journal › Article
To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C5-containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Environmental Science and Technology|
|Early online date||2017 Jan 4|
|Publication status||Published - 2017|
No data available
Related research output
Characteristics of Particulate Emissions from Low Temperature Combustion and Renewable Fuels: Aerosol Mass Spectrometry of Refractory Carbonaceous ParticlesVilhelm Malmborg, 2020 Jan 17, Lund: Department of Design Sciences, Faculty of Engineering, Lund University. 96 p.
Research output: Thesis › Doctoral Thesis (compilation)